Method and apparatus for uninterrupted delivery of radiographic dye

ABSTRACT

A method and apparatus for injecting radiographic dye during angiography. A deformable holding chamber is interposed between a contrast dye bottle and a syringe manifold. A one-way valve and an integral disconnect/flow-stop are connected between the bottle and the holding chamber. A vent is provided in the holding chamber, which can include a second one-way valve. Squeezing and releasing the deformable chamber fills the chamber from the bottle. The holding chamber contains a floating baffle which acts as a shut off valve by plugging the chamber outlet if the chamber becomes empty. The syringe is used to withdraw dye from the holding chamber. If dye remains in the bottle after performance of the procedure, the disconnect/flow-stop fitting can be disconnected, and the dye can be saved.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation patent application of U.S. patent applicationSer. No. 08/661,374, filed on Jun. 11, 1996, now U.S. Pat. No. 5,779,666and entitled "Method and Apparatus for Uninterrupted Delivery ofRadiographic Dye", which was a continuation of U.S. Ser. No. 08/336,252,filed Nov. 7, 1994, now U.S. Pat. No. 5,533,978, both of which areincorporated by reference herein.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention is in the field of angiography using a liquid contrastdye.

2. Background Information

A procedure commonly performed is the catheterization of thecardiovascular system of a patient, requiring the performance ofangiography to assist the physician in visualizing the catheter andother instruments within the blood vessels. Typical of procedures forwhich catheterization is performed are atherectomy and angioplastyprocedures. During angiography, a radiopaque contrast dye or othermedium is usually injected into the vascular system to render the lumenof the vessel visible via radiographic equipment.

The contrast dye is typically provided in containers such as bottleswith puncturable receptacles. The receptacle is punctured with a spike,which can be vented, and the spike is typically connected to theproximal end of a flexible tube. The bottle is hung from a stand toprovide a hydrostatic head, and the distal end of the flexible tube canbe connected to a manifold or other valving device. The manifold is alsoconnected to a syringe and to the proximal end of a guide catheter, thedistal end of which is inserted into the vascular system of the patient.

During the catheterization procedure, when the physician wishes toinject dye into the blood vessel, the plunger of the syringe is firstwithdrawn, with the manifold or other valves aligned as required toallow flow of dye from the contrast bottle, through the tubing and themanifold, to the syringe. The manifold valves are then realigned asnecessary, to allow flow from the syringe to the guide catheter, and theplunger is pushed into the syringe to dispense contrast dye into thepatient's vascular system, through the manifold and the guide catheter.After the syringe is emptied, if another dye injection is required, thephysician again draws dye from the bottle into the syringe and dispensesthe dye into the guide catheter.

Two problems can result from this conventional method of dye injection.First, the method is unnecessarily expensive, because it wastes largeamounts of very expensive contrast dye. Each cardiovascularcatheterization procedure typically only requires about 70 or 80milliliters of contrast dye. After performance of the typical procedure,some of the contrast dye usually will be left in the bottle. Thisremaining dye can not be used in a subsequent procedure on anotherpatient, because of the risk of contamination. In other words,contaminated fluids from the first patient might conceivably flow backthrough the syringe to the contrast bottle, subsequently contaminatingthe second patient. To guard against this possibility, the contrast dyeremaining in a bottle typically is discarded. If large bottles are used,a large amount of dye can be wasted. Considering that the contrastmaterial costs approximately one dollar per milliliter, this practiceresults in substantial unnecessary expense.

Secondly, when the physician repeatedly fills the syringe, if thecontrast bottle approaches empty, air will eventually be drawn into thetubing and possibly into the syringe. This requires stopping thecatheterization procedure while a new bottle of fluid is attached, andwhile the air is purged from the syringe and the tubing. If smallerbottles are used to limit waste, additional time in surgery can berequired for repeatedly changing bottles and repriming the flowpath.Given the invasive nature of cardiac catheterization in particular, andgiven the fact that blood flow in the affected vessel is substantiallyreduced during the procedure, any delay in the procedure is veryundesirable.

It is an object of the present invention, then, to provide a method andapparatus for injecting radiographic dye into a vascular system, whichwill allow the use of essentially all of the contrast material in abottle before discarding the bottle, without fear of contamination. Itis a further object of the present invention to provide a method andapparatus for injecting radiographic dye into a vascular system, whichwill allow the replacement of an empty contrast bottle with areplacement bottle, without stopping the procedure. Finally, it is anobject of the present invention to provide a method and apparatus forinjecting radiographic dye into a vascular system, which is easy andeconomical to implement.

BRIEF SUMMARY OF THE INVENTION

A preferred embodiment of the present invention, for illustrativepurposes only, includes a method and apparatus for injectingradiographic dye during cardiovascular catheterization that interposes adeformable holding chamber between the contrast bottle and the syringemanifold. Flow control devices are installed to allow rapid filling ofthe holding chamber, replacement of an empty bottle with a full bottlewithout interrupting the procedure, and separation of the holdingchamber from a partially emptied contrast bottle to permit use of theremainder of the contrast dye in a subsequent procedure. A tube isconnected between the vented spike in the contrast bottle and theholding chamber, with two flow control devices installed at intermediatepositions along the tube. A floating baffle of latex or some otherimpermeable membrane, stretched across a floating frame, is containedwithin the holding chamber. As the level of dye in the holding chamberreaches the bottom of the chamber, the impermeable membrane covers andplugs the chamber outlet to prevent air from entering the outlet linefrom the holding chamber.

The first flow control device in the tube between the vented spike andthe holding chamber is a disconnect fitting with an integral automaticflow-stop. The fitting is a device available on the market, which hastwo halves joined by mating threads. Each half of the fitting isconnected to the tubing so as to cause all flow through the tubing toflow through the fitting. Disconnection of the fitting, therebydisconnecting the tubing, is accomplished by separating the two halvesof the fitting at the threads. The upstream half of the fitting,connected to the tubing leading from the contrast bottle, contains anintegral automatic flow-stop. When the two halves of the fitting areseparated at the threads, the flow-stop automatically closes, preventingflow through the upper half of the fitting.

The second flow control device is a one way valve which is installed toallow flow only from the contrast bottle into the holding chamber. Theone way valve can be one of a number of such devices available on themarket. It should be suitable for preventing even low flow rates in thereverse direction. This device is installed in the tubing between thedisconnect/flow-stop fitting and the holding chamber. Therefore, the oneway valve prevents flow of fluid from the holding chamber back to thecontrast bottle while the tubing is still connected, and it preventsflow of fluid out of the holding chamber to the atmosphere after thetubing is disconnected.

A third device which can optionally be installed on the tubing betweenthe contrast bottle and the holding chamber is an air-in-line sensor,which can be one of several available on the market. It can, forinstance, be ultrasonically operated, or based on infrared orphotoelectric technology. This sensor can detect air or other gas in thetubing, such as an air bubble which might enter the tubing if thecontrast bottle empties unnoticed by the physician. When air is sensedby this sensor, an alarm is sounded, and the contrast bottle can bereplaced with a full bottle before air enters the tubing leading to thesyringe manifold. This obviates the need to stop the procedure, sincecontrast medium will still be available in the holding chamber for anyinjections that are needed during bottle replacement. This can alsofacilitate the removal of air from the tubing after replacement of thecontrast bottle, since as will be seen, repriming of the holding chamberwill automatically remove the entrapped air from the tubing upstream ofthe holding chamber. As an alternative, the air sensor can be installedon the outside of the holding chamber at a selected level to warn thatthe level of dye in the chamber is falling. The selected level would bebelow the normal full level but above the empty level to insure thatseveral injections are still available while the dye bottle is beingexchanged.

The deformable chamber is also fitted with a pierceable seal and a ventopening. The pierceable seal allows secondary injections or connectionsas desired. The vent opening is fitted with a second one way valve,which can be operated by a low pressure differential, like the first oneway valve, or it can be a high pressure crack valve which opens onlyupon seeing a relatively high pressure differential across the valve.The second one way valve is oriented to allow flow only out of theholding chamber to the atmosphere. If desired, a manual stop valve canbe installed in the vent line between the second one way valve and theholding chamber. The manual stop valve is required only if the one wayvalve in the vent is a typical one way valve having a relatively lowcracking pressure. If the second one way valve is a high pressure crackvalve, the manual valve is not needed.

In order to use the apparatus of the present invention, the vented spikeis inserted into the receptacle on the contrast bottle, and the bottleis hung on a stand. If installed, the manual stop valve on the holdingchamber vent is opened. Then, the deformable holding chamber is squeezedand released one or more times, to expel air out the chamber vent anddraw contrast dye into the chamber from the contrast bottle. Thisprocess is repeated until the holding chamber contains the desiredamount of dye, preferably about 30 milliliters. Then, the manual valveon the holding chamber vent is closed, if one is installed. Partialfilling of the holding chamber leaves an air space in the chamber, whichacts as a contamination barrier when combined with the presence of thefirst one way valve in the inlet tube.

The presence of the vent on the holding chamber allows the holdingchamber to be filled much more rapidly than if the venting of theapparatus were to be done entirely through the dye bottle, as was seenin the prior art device. Moreover, the presence of the second one wayvalve in the vent line promotes the rapid filling of the holdingchamber. Squeezing the holding chamber forces air out the vent throughthe second one way valve. When the holding chamber is released andallowed to expand to its original size, the second one way valveprevents air from flowing back into the holding chamber through thevent. This ensures the formation of a vacuum in the holding chamber todraw dye into the chamber from the dye bottle, via the first one wayvalve.

When the physician wishes to inject dye into the patient, the manifoldvalves are aligned to allow flow from the holding chamber into thesyringe. Then, the syringe plunger is withdrawn to draw dye from theholding chamber into the syringe. As dye is drawn into the syringe fromthe holding chamber, replacement dye is drawn into the holding chamberfrom the contrast bottle. The manifold valves are then aligned to allowflow from the syringe into the guide catheter, and the plunger is pushedinto the syringe to dispense dye into the patient.

If the procedure is completed without using all of the dye in thecontrast bottle, the bottle can be removed and saved for anotherprocedure by disconnecting the disconnect/flow-stop fitting. Theequipment downstream from the fitting, including the lower half of thefitting, can be discarded. The equipment upstream of the fitting is safeto save, since the interposition of the holding chamber and the one wayvalve between the disconnect/flow-stop fitting and the patient insuresthat no contamination can reach the fitting.

If the contrast material in the bottle is exhausted before the procedureis complete, the bottle can be removed by removing the spike from thebottle and inserting it into a new bottle. After a replacement bottle isconnected, the holding chamber and the tubing from the contrast bottlecan be reprimed by squeezing and releasing the holding chamber asbefore, if required.

The novel features of this invention, as well as the invention itself,will be best understood from the attached drawings, taken along with thefollowing description, in which similar reference characters refer tosimilar parts, and in which:

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a schematic diagram of a typical dye injection apparatus as isknown in the art; and

FIG. 2 is a schematic diagram of the dye injection apparatus of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

As seen in FIG. 1, a typical dye injection apparatus as is known in theart includes three basic components. Specifically they are a contrastdye bottle 12, a dye manifold 16, and a syringe 50. The contrast bottle12 is connected to the manifold 16 by a vented spike 24 and a length oftubing 20. The manifold 16 is also connected to a branch of a guidecatheter (not shown) by a second length of tubing 22.

The vented spike 24 is inserted into the bottle 12 via a receptacle inthe mouth of the bottle 12. As fluid is drawn from the bottle 12, air isdrawn into the bottle 12 through the branch of the spike 24, as shown bythe arrow. The fluid conduit of the spike 24 is connected to theproximal end of the flexible tubing 20. The distal end of the tubing 20is connected to an inlet valve 42 on the manifold 16. Typically, amanifold 16 will also have other valves 44, 46, as well as an outletvalve 48. A proximal end of the second tubing 22 is connected to theoutlet valve 48. Finally, the syringe 50 is connected to the manifold16. The manifold 16 could have various types of valves, including manualvalves or check valves, to control the flow of the contrast dye. Indeed,the manifold 16 could be replaced by a multi-ported ball valve. However,the functioning of the apparatus can be most easily illustrated bydiscussion of a manifold 16 having manual valves as shown.

Once connected as shown, the known apparatus must be primed by drawingdye into the syringe and dispensing it into the guide catheter,including the purging of all air bubbles from the manifold 16 and thetubing 20. This is a time consuming operation. When it is desired toinject contrast dye into the patient, the physician withdraws theplunger of the syringe 50, with inlet valve 42 open and outlet valve 48closed. When the syringe 50 is filled with dye, inlet valve 42 is shutand outlet valve 48 is opened. Then, the plunger is inserted back intothe syringe 50, dispensing the dye through the manifold 16, and throughthe tubing 22, to the guide catheter. Each injection will typicallydispense approximately 7 ml. of dye. Repeated injections are repeated asrequired. After the angiography procedure has been completed,approximately half of the dye in bottle 12 will remain. The entireapparatus, including the remaining dye, must be discarded, since thereis no assurance that contaminated fluid has not migrated back up throughthe apparatus into the bottle 12.

FIG. 2 shows a preferred embodiment of the apparatus of the presentinvention 10. The contrast bottle 12 is ultimately connected, as before,to the manifold 16 and the syringe 50. In this case, however, apparatusis interposed between the bottle 12 and the manifold 16 to ensure thatcontamination does not migrate back to the bottle 12, and to facilitatedisconnection of the bottle 12 from the other apparatus, to allow savingthe remaining dye in the bottle 12, or to allow replacement of an emptybottle with a full bottle.

The intervening apparatus consists of a deformable holding chamber 14,which is connected to the bottle 12 by several additional components ina flow path 18. Connected to the fluid conduit of spike 24 is theproximal end of a length of tubing 26, forming a portion of the flowpath 18. Continuing along flow path 18, the distal end of the tubing 26is connected to the proximal end of a disconnect/flow-stop fitting 28.The disconnect/flow-stop fitting 28 consists essentially of twoportions, a flow-stop portion 32 and a threaded disconnect portion 30.The fitting 28 can be one of a number of such fittings available on themarket. When the threaded disconnect portion 30 is disconnected, therebybreaking the flow path 18, the integral flow-stop portion 32automatically stops flow through the flow path 18 from the bottle 12.

The distal end of the fitting 28 is connected to the proximal end of asecond length of tubing 34, the distal end of which is connected to theproximal end of a one-way valve 36. The one-way valve 36 allows flowonly from the bottle 12 toward the holding chamber 14, as shown by thearrow. The one-way valve 36 can be one of a number of such valvesavailable on the market. The distal end of the one-way valve 36 isconnected to the proximal end of a third length of tubing 38, completingflow path 18. Indeed, the three lengths of tubing 26, 34, 38 can be seento constitute essentially a single tubing with the disconnect fitting 28and the one-way valve 36 interposed therebetween.

The tubing 38 can have attached thereon an air-in-line sensor, or bubbledetector 60. The bubble detector 60 can be one of several such devicesavailable on the market, which can operate on ultrasonic, photoelectric,or infrared technology. When a gas bubble is detected in the tubing 38,the sensor 60 will give an alarm signal to alert personnel to the needto replace the bottle 12 with a full bottle.

Alternatively, an air sensor 60' can be mounted on the holding chamber14 to determine when the dye level has fallen below a selected level.Normally, the sensor 60' will be mounted at a level selected to be belowthe normal fill level in the chamber 14, but above the bottom of thechamber 14 Ideally, the level at which the sensor 60' is mounted willleave at least enough dye to supply several injections of dye after theair alarm is given. As dye is withdrawn from the holding chamber 14, apartial vacuum in the holding chamber 14 will draw additional dye fromthe bottle 12, causing the dye level in the holding chamber 14 to remainrelatively constant. This means that the floating baffle 52 willnormally remain above the level at which the sensor 60' is mounted, andthe sensor 60' will not detect the presence of air. If the bottle 12empties, repeated injections of dye into the patient will cause thebaffle 52 to drop below the level of the sensor 60', and the air alarmwill be energized.

An injection fitting 40 and a vent 54 are also mounted on the deformablechamber 14. The injection fitting 40 is fitted with a pierceable seal,allowing the injection of secondary fluids with a hypodermic needle, orallowing the connection of a secondary set of tubing as desired. Thevent 54 is fitted with a stop valve 56 and a second one-way valve 58.The second one-way valve 58 is installed so as to allow flow only out ofthe holding chamber 14 to the atmosphere, as shown by the arrow. If theone-way valve 58 is a high pressure crack valve, the manual valve 56 isnot needed.

The holding chamber 14 itself is a deformable chamber which isconstructed so as to return to its original shape after being squeezedand released, with the resiliency being sufficient to draw dye out ofthe bottle 12 during return of the chamber 14 to its original shape. Itshould have visibility through at least a portion of its side wall, toallow personnel to see the level of dye therein. It should also havegraduated markings on its side, and its capacity should be at least 30ml. The baffle 52, such as a floating baffle, can be provided within thechamber 14, to prevent the entrainment of air in the dye by directimpingement of the stream of dye on the reservoir of dye in the bottomof the chamber 14. The baffle 52 consists of a floating frame and animpermeable membrane such as a latex membrane. As dye falls on top ofthe membrane, it flows around the outside of the frame, which looselyfits the inner diameter of the holding chamber 14. As the level of dyein the holding chamber 14 drops, the floating baffle 52 drops on top ofthe outlet of the chamber 14 and the impermeable membrane stops all flowout of the outlet.

With the apparatus 10 connected as shown in FIG. 2, and with contrastdye in the bottle 12, the vent valve 56 is opened. Then, the holdingchamber 14 is squeezed and released several times to expel air from theholding chamber 14 through the vent 54, and to draw dye into the chamber14 through the flow path 18. Filling of the chamber 14 is rapid becauseof the pumping effect of the deformable chamber 14, and because of thelarge capacity of the vent 54, as compared to venting only through therelatively small vented spike 24 as in the prior art. When the desiredlevel of dye, typically about 30 ml., is in the holding chamber 14, thevent valve 56 is closed. This will leave an air gap in the top of theholding chamber 14.

When an injection is required, the plunger of the syringe 50 iswithdrawn, with inlet valve 42 open and outlet valve 48 closed, and thedye is then dispensed by reinserting the plunger into the syringe 50,with the inlet valve 42 closed, and with the outlet valve 48 open. Asmentioned before, these valves 42,48 could be check valves or a singlemulti-port ball valve. As dye is withdrawn from the chamber 14 by thesyringe 50, it is replaced by dye flowing from the bottle 12 to thechamber 14, because of the partial vacuum created in the chamber 14.Repeated injections can be accomplished by repeating the procedure asrequired.

If dye material is remaining in the contrast bottle 12 after theangiography is completed, the disconnect fitting 30 can be threadedlydisconnected from the integral flow-stop 32, whereupon the integralflow-stop 32 will stop flow from the bottle 12. Alternatively, the spikeconnector 24 can be removed from the bottle 12, and a new spikeconnector 24 can be reinserted in the bottle 12 when the bottle 12 isused again. Since the patient has at all times been separated from thebottle 12 by an air gap in the holding chamber 14 and by the one-wayvalve 36, the dye remaining in the bottle 12 is sterile and can be usedin a subsequent procedure.

If the bottle 12 becomes empty during the procedure, the bubble detector60, 60' if installed, will warn attendants to replace the bottle 12 witha full bottle. Since there will be approximately 30 ml. of dye availablein the chamber 14, there is ample time for the bottle to be replaced.After bottle replacement, the deformable chamber 14 can be repeatedlysqueezed and released, with vent valve 56 open if present, to quicklyreturn the level of dye in the chamber 14 to the desired level. Thiseliminates the need to purge air from the tubing 20, and repriming isaccelerated by the deformability of the chamber 14. If the bubbledetector 60, 60' is not installed, the holding chamber 14 affords anadditional visible indication of the amount of dye remaining.

Further, flow path 18 includes a number of restricted passageways in theflow-stop 32 and in the one-way valve 36 which offer some resistance toliquid flow. Therefore, if the bottle 12 empties, followed by theemptying of the flow path 18, drawing of dye into the syringe 50 willbecome increasingly easy, because of the fact that air rather thanliquid dye is being drawn through the flow path 18. This will offer thephysician an additional indication that the bottle 12 is empty, whiledye is still available in the chamber 14. If the dye level in theholding chamber 14 falls sufficiently, the baffle 52 will settle ontothe outlet of the chamber 14 and act as a shut off valve to prevent airfrom entering the outlet line.

While the particular invention as herein shown and disclosed in detailis fully capable of obtaining the objects and providing the advantageshereinbefore stated, it is to be understood that this disclosure ismerely illustrative of the presently preferred embodiments of theinvention and that no limitations are intended other than as describedin the appended claims.

I claim:
 1. A fluid delivery system, comprising:a fluid reservoir, saidfluid reservoir having an outlet; a deformable fluid holding chamber,said holding chamber having an inlet and an outlet; a fluid shut offvalve in said holding chamber for shutting off said outlet of saidholding chamber when said holding chamber becomes empty; a tubularconduit connecting said outlet of said reservoir in fluid flowcommunication with said inlet of said holding chamber; a one way valveconnected in said tubular conduit, said one way valve permitting flowonly from said reservoir to said holding chamber; and an air vent influid flow communication with said holding chamber.
 2. A fluid deliverysystem as recited in claim 1, further comprising a vent valve connectedin fluid flow communication with said air vent, said vent valve beingcapable of selectively permitting air flow from said holding chamber tothe atmosphere.
 3. A fluid delivery system as recited in claim 2,wherein said vent valve is a manual valve.
 4. A method of injectingradiographic dye into a vascular system of a patient, said methodcomprising:providing a radiographic dye reservoir, a deformable dyeholding chamber connected to said dye reservoir via a one way valve, ashut off valve within said holding chamber, and a vent on said holdingchamber; squeezing said holding chamber to expel air from said holdingchamber to the atmosphere through said vent; stopping flow through saidvent; releasing said holding chamber to allow said holding chamber toexpand and draw dye from said reservoir into said holding chamberthrough said one way valve; withdrawing dye from said holding chamberwith a syringe; and dispensing dye from said syringe into a vascularsystem of a patient.
 5. A method of injecting radiographic dye asrecited in claim 4, further comprising:providing a vent valve in fluidflow communication with said vent; and stopping said flow through saidvent with said vent valve.
 6. A method of injecting radiographic dye asrecited in claim 4, further comprising:providing a manual vent valve influid flow communication with said vent; and stopping said flow throughsaid vent by closing said manual vent valve.